At least 51 people died on Thursday when a bus and a truck collided about 100 km (60 miles) north of Zambian capital Lusaka, police said.
Police spokeswoman Elizabeth Kanjela said the death toll could rise as soldiers and firefighters were still checking the wreckage for trapped bodies.
"So far we have counted 51 bodies but there could be one or two people more that are still trapped,'' Kanjela said. The cause of the accident was under investigation, she said.
Zambian roads are extremely dangerous and buses and other vehicles are often overloaded or poorly maintained.